The old castle has which has an area of about 15,000 square meters is located at the entrance to Meshkin-Shahr on the Ardebil road and on natural foci with a height of 50 meters and consists of six turrets with thick walls of brickwork and adjoining small chambers. The approximate height of the castle is 1416 meters above sea level.
The old castle of Meshkinshahr is one of the works of the Sasani era and has a special strength and was used in wars helped us defend against the invasion of enemies as a sanctuary. The first monument of this castle was built in the Shaopur II Sassani era in 337 AD, according to the orders of the Sultanate of Sulawesi in Siahai during 6 years.
This building was registered in the year 1345 with the number 618 in as a national monument. Exploration was first carried out in the castle in 1366, and in the year 1367 explorers continued their work in the second phase of exploration.
In the archaeological excavations in the old castle, signs of cultural items, hand-made pottery and chopped wood chips , gray metal and bronze metal related to the 3rd Iron age are found which are attributed to civilizations known as the "Urartu" on the brink of the formation of the state of Mada And in some cases, even earlier, signs of their culture and civilization have been observed in most parts of Azerbaijan.
There is a pencil on the Sassanid Pahlavi line on the northwest front of the building located 150 meters in the Chiavo river. The castle plan is an irregular tuft along the northwest and southwest. The length of the side is 90 meters and its south side is 237 meters and the width of the castle on the west side is 115 meters and on the east side it measures to 91 meters .In the two corners of northwest and south there are circular towers which are 6 meters and 10 meters in diameter. The Eastern side of the northern monument has two towers of 7.5 meters and 6 meters in diameter with better sides than the other towers. The walls of the castle walls are made of stone, plaster and lime mortar, and the rest of it is made by clay and its congresses are made of flowers.